Researchers at Scotland’s University of Aberdeen released a study suggesting obesity is a problem that’s plaguing couples looking to conceive. Obesity in women is known to cause fertility problems, and with the revelations of this new study, men looking to start a family must also consider how their weight can affect their sperm production.

“We felt that it was possible males [being] overweight might contribute to fertility problems, particularly since it is a known risk factor for problems in conceiving among women,” said lead researcher Dr. Ghiyath Shayeb in a statement.     

Though other factors detrimental to sperm production, such as smoking, drinking and age, were taken into consideration, “our findings … seem to suggest that men who are trying for a baby with their partners, should first try to achieve an ideal body weight.”    

Analyzing the sperm of 2,037 men who were trying to conceive, the researchers found that obese men, identified with a body mass index above 30, produced 40 percent more abnormal sperm and 60 percent less seminal fluid. The latter could be attributed to hormone levels, the overheating of testicles surrounded by extra flesh, and an unhealthy diet. The abnormal sperm, with its damaged DNA, can result in increased chances of miscarriages and infertility.   

The men were all separated into four groups based on body mass index, and those ranging from 20 to 25 produced more normal sperm in higher volumes. Sperm activity and concentration remained relatively the same for all four groups.

"Adopting a healthy lifestyle, a balanced diet, and regular exercise will, in the vast majority of cases, lead to a normal BMI," said Dr. Shayeb, who presented the research at Barcelona’s European Society of Human Reproduction and Embryology conference.

Researchers are now looking to study the body mass index of men among fertile and infertile couples, looking to see if poor semen quality has a direct link to decreased fertility.

In additional to obesity adversely affecting men’s ability to conceive, past studies have indicated that obesity in women caused ovulation and menstruation problems, leading to decreased fertility. The additional fat cells increased estrogen production, and this hormone imbalance caused the ovaries to function abnormally. The extra weight also interfered with the body’s ability to absorb fertility drugs, which made it more difficult for conception.